Video: Atlas 5 GPS 2F-8 Launch Highlights

The mission, dubbed Cert-2 by United Launch Alliance, is the final mission required before the rocket can begin launching national security missions. Liftoff is set for the beginning of a three-hour window at 6 a.m. EDT (1000 UTC).

NASA has agreed to consider a Boeing proposal to extend the first piloted test flight of its commercial CST-100 Starliner crew capsule from two weeks to up to six months with an extra crew member for the International Space Station, hedging against potential delays that could jeopardize U.S. crew access to the orbiting outpost.

This is our comprehensive fact sheet previewing the United Launch Alliance Atlas 5 rocket deployment of the classified NROL-42 payload for the National Reconnaissance Office.